IB/mlx4: avoid a -Wmaybe-uninitialize warning

There is an old warning about mlx4_SW2HW_EQ_wrapper on x86:

ethernet/mellanox/mlx4/resource_tracker.c: In function ‘mlx4_SW2HW_EQ_wrapper’:
ethernet/mellanox/mlx4/resource_tracker.c:3071:10: error: ‘eq’ may be used uninitialized in this function [-Werror=maybe-uninitialized]

The problem here is that gcc won't track the state of the variable
across a spin_unlock. Moving the assignment out of the lock is
safe here and avoids the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/net/ethernet/mellanox/mlx4/resource_tracker.c

@@ -1605,13 +1605,14 @@ static int eq_res_start_move_to(struct mlx4_dev *dev, int slave, int index,
 			r->com.from_state = r->com.state;
 			r->com.to_state = state;
 			r->com.state = RES_EQ_BUSY;
-			if (eq)
-				*eq = r;
 		}
 	}
 
 	spin_unlock_irq(mlx4_tlock(dev));
 
+	if (!err && eq)
+		*eq = r;
+
 	return err;
 }